The Chrome 85 Web UI on Linux Mint 20 produced a 62 MB file with the corrupted name
12.44.03-12.45.21[M][0@0][0].mp4 in about 20 seconds.
Surveillance Pro on Windows 10 produced a 62 MB file with name
AMC-IP8M-2496E_ch1_20200918124403_20200918124521.mp4 in about 2 minutes. Other formats where offered ASF, AVI, original (DAV) all of which produced about the same file size and took several minutes to produce.